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Патент USA US3077048

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Feb. 12,< 1963
w. L. CARLSON
3,077,030
METHOD OF‘ FORMING LOCATORS
Filed May 21, 1959
r
2 Sheets-Sheet 2
IN VEN TOR.
I
[Mi/bur Z. Carbon
BY
azm,
._
Hgs ATTORNEY
r0
EC
3,077,030
Patented Feb. 12, 1963
1
2
3,077,030
and the aluminum gear reduction housing causes the alu
minum of flow ahead of the spinning tool and into the
corner or edge of the motor frame thereby forming a
' METHOD OF FORMING LOCATORS
Wilbur L. Carlson, Rochester, N.Y., assignor to General
Motors Corporation, Detroit, Mich., a corporation of
precise locator.
After the locators have been formed in the gear reduc
tion housing, the two parts can be separated for subse
Delaware
Filed May 21, 1959, Ser. No. 814,811
7 Claims. (Cl. 29-407)
quent subassembly operations. However, the mated parts
are kept together so that when the ?nal assembly stage
is reached the two parts can be reassembled on the ex
This invention pertains to a method of forming pre~
Icise locators on an article which is to be subsequently 10 truded locators to form a completed unit.
Further objects and advantages of the present in
assembled with a mating article, and also to an article
, . It is often times necessary to accurately locate mating
vention will be apparent from the following description,
reference being had to the accompanying drawings, where
‘parts prior to ?nal assembly of the parts to enable sub
in a- preferred embodiment of the present invention is
vsequent'subassembly operations on the parts themselves
clearly shown.
In the drawings:
having integral extruded locators.
and assure proper ?tting of the parts during the ?nal as
'_sembly operation. For example, in the manufacture .of
small direct current motors of the general type disclosed
‘ in'c'opending application SN. 680,238 ?led August 26,
FIGURE 1 is a view, partly in section and partly in
elevation, of the mating parts as held in a clamping ?x
‘ tion housing must be accurately located with respect to
along line 3-3 of FIGURE 2.
ture during the locator forming operation.
FIGURE 2 is a fragmentary, sectional view taken
3 ‘1957, in the name of Simmons et al. and assigned to the 20
along line 2-—2 of FIGURE 1.
assignee of the present invention, wherein the motor in
FIGURE 3 is a fragmentary, sectional view taken
I eludes anintegral worm gear reduction, each gear reduc~
,
FIGURE 4 is an end view of the mating part with th
I present invention relates to a method of forming accu 25 extruded locators.
FIGURE 5 is a sectional view taken along line 5—-5
\ rate locators on a gear reduction housing composed of
of FIGURE 1 after the locators are formed on one of
“aluminum. However, this embodiment is to be con
the mating parts and with the arbor removed.
strued only ,_by way of example, and not by way of limi
With particular reference to FIGURE 1, a single piece
tation, since it is readily apparent that the method dis
, closed therein is applicable to numerous manufactured 30 sheet metal motor frame 10 of substantially rectangular
con?guration and a die cast aluminum gear reduction
jarticles having mating parts. Accordingly, among my
housing 12 comprise the mating parts of the disclosed as
objects are the provision of a method of forming locators
sembly. The frame 10 may be constructed in accordance
' on one' of a pair of mating parts; and the further pro
its mating frame. The disclosed embodiment of the
}vision of a method of forming precise locators utilizing
35
a spinnin g technique.
. ,, T he-aforementioned and other objects are accomplished
. in the present inventionvby prelocating and clamping to
' gether the mating parts and thereafter forming a plu
rality of locators on one of the parts by a spinning opera
tion.
Speci?cally, in the disclosed embodiment the 40
_ mating parts, comprise a substantially rectangular motor
with the aforementioned copending application and thus
includes overlapping end portions 14 and 16, which are
suitably interconnected, and an intermediate arcuate por
tion 18 on the opposite side thereof. The end portions
20 and 22 opposite the overlapped portions 14 and 16
are bulged outwardly so as to accommodate parts of the
motor assembly.
‘
The upper edges of the frame designated by numeral
2d and shown clearly in FIGURE 5, are smooth and lie
‘ frame and a die cast aluminum gear reduction housing.
in a single plane. The frame is composed of annealed
in- carrying out the present invention it is essential that
hot rolled steel, and as shown in FIGURE 1, has a ?eld
‘the mating parton which the locators are not formed
'‘ be composed of material having a strength and hard 45 coil assembly 26 mounted therein. The ?eld coil assem
bly comprises a pole piece 28, which is suitably attached
: ness substantially greater than the part on which the 10
cators are spun in situ.
Thus, for example, when the part
to the overlapped end portions 14 and 16, and a coil as
i, having the locators is composed of aluminum, the mat
inglpart maybe composed of annealed hot rolled steel.
sembly 30. A substantially cylindrical air gap 32 is
formed between the pole piece 28 and the arcuate portion
The gear reduction housing and the frame are accu
‘ rately prelocated prior to the spinning operation by cen
18 of the fame. Due to variations in the thickness of
th: steel strip from which the frames 10 are made, it will
be appreciated that there may be an appreciable varia
tion in the dimensions of thetrames at the gear reduction
.. trally‘locating the gear reduction housing on one end
. of the motor frame, which includes a ?eld coil assembly.
.' To achieve this ‘result, an arbor is concentrically located
end.
'
.
. within the air gap, the arbor having a shaft extending 55
The gear reduction housing 12 includes a substantially
. into the sleeve bearing of the gear reduction housing.
flat surface 34 having a pair of holes 36 therein through
‘1' The gear reduction housing and the frame are then
which tie bolts are adapted to extend, and a centrally lo
clamped together and high speed spinning tools are
cated opening 38 which, as shown in FIGURE 1, is ?tted
brought into engagement with the aluminum gear reduc
, tion housing. The spinning tools are pressed against 60 with a sleeve bearing 40. The sleeve bearing 40 is coaxial
with a cylindrical bore 42 of the housing 12, and the
. the housing with a force substantially equal to the com
housing 12 includes a second cylindrical bore 44 located
pressive strength of the aluminum and are located par
in a plane at right angles to the bore 42 and intersecting
tially over a corner or edge of the frame. The localized
the same. The bore 44 is adapted to receive a worm gear,
heat created by the friction between the spinning tool
3
not shown, the shaft of which is journalled in an opening
46 in the housing 12. The motor armature shaft, not
shown, may be formed with an integral worm having
driving engagement with the worm gear. The housing
12 includes a plurality of integral bosses 48 which are
closed constitutes a preferred form, it is to be understood
that other forms might be adopted.
What is claimed is as follows:
1. The method of forming locators on a ?rst part which
After the ?eld assembly 26 has been assembled within
is to be assembled with a second part including the steps
of clamping the parts in the proper assembled posi
tion, engaging the ?rst part with a rotating spinning tool
the frame it), and the sleeve bearing 4t? has con assem
over an area including an edge of the second part, and
used as motor mounts.
bled with the housing iii, the frame and the housing are
applying pressure to the spinning tool to cause localized
clamped together in a ?xture. As shown in FIGURE 1, 10 ?ow of the ?rst part due to localized softening of the ?rst
the ?xture includes a base 51“: havimr an upstanding leg
part by heat generated due‘to frictional engagement be
52 with an upper arm portion 54. An arbor 56 is posi
tioned within the air gap 32, the arbor 56 having an inte
tween the spinning tool and the ?rst part.
2. The method of forming locators on a ?rst part
gral shaft 58 projecting through the sleeve bearing 46}.
which is to be assembled with a second part including
The arbor 56 is used to properly locate the housing rela 15 the steps of clamping the parts in the proper assembled
tive to the frame 1%. After these parts are properly lo
position, rotating and moving a spinning tool longitudi
cated they are clamped together by any suitable means,
nally against the ?rst part over an area including an edge
such as a screw device 69 indicated in FIGURE 1.
of the second part, and applying pressure to the spinning
Thereafter, one or more spinning tools 62 composed
tool substantially equal to the compressive strength of
of a relatively hard material, such as sintered carbide, 20 the material or" the ?rst part to cause localized ?owing
are brought into engagement with the upper surface of
of the pair due to localized softening of the ?rst part by
the housing 12. The tools 62 have a cylindrical cross
the heat generated by frictional engagemnet between the
section and the ends thereof are substantially ?at, as
spinning tool and the ?rst part.
shown in FIGURE 1. The tools 62 are rotated at a
3. The method of forming locators on a ?rst part which
relatively high speed, that is, between 10,000 and 20,060 25 is to be assembled with a second part which comprises,
rpm. and are moved longitudinally under pressure sub
clamping the parts in the proper asscmbled'positiom'and
stantially equal to the compressive strength of the alumi
engaging the ?rst part with a rotating spinning tool over
num. As shown particularly in FIGURES 2 and 3, part
an area including an edge of the second part and forcing
of each spinning tool overlaps the upper edge 24 of the
the spinning tool longitudinally against ‘the ?rst part to
frame 10. The distance of the overlap indicated by nu 30 form a locator by ?owing the material of the ‘first part
meral 64 in FIGURE 3 is preferably equal to substantially
‘ahead of the ‘spinning tool due to localized‘softening of
one-fourth of the diameter of the spinning tool 62. Due
the ?rst part caused by heat generated due to frictional
to high speed rotation of the spinning tool under pres
sure in the direction of arrow 66 of FIGURES l and 3,
engagement between the‘spinning tool and the ?rst part.
subsequent assembly operations. To complete the motor
ing spinning tool over an area including a corner of the
4. The method of forming locators on a ?rst part
the friction between the spinning tool and the aluminum 35 which is to be assembled with a ‘second part, the ?rst
housing creates localized heating of the housing. This
part being composed of a material having a strength and
localized heating of the housing causes the aluminum to
hardness substantially less than the second part, which
ilow ahead of the spinning tool into the corner, or over
comprises, clamping the parts in the proper assembled
the edge, of the motor frame 19 thereby forming an inte
position, engaging the ?rst part with a ‘rotating spinning
gral extruded locator 68. In order to reduce the time 40 tool over an area including an edge of the second "part,
to a minimum and to improve the quality of the extruded
and applying pressure to the spinning tool substantially
locators, the pressure exerted on the spinning tool 62 in
equal to the compressive strength of the material of the
the direction of the arrow 66 must be as high as possible,
?rst part to form a locator by ?owing the material voi‘
and thus is only slightly less than the compressive strength
the ?rst part over the edge of the second part, due ‘to
of the material to be extruded. in this manner, the heat 45 localizing softening of the ?rst ‘part caused by heat
generated by the friction between the tool and the part to
generated due to frictional engagement between the spin
ning tool and the ?rst part.
'
be extruded- brings ‘localized portions of the material to
‘the ?owing temperature in a relatively short time. The
5. The method of forming locators on a ?rst part
length 76 of each locator is substantially equal to the
which is to be assembied with a second part, the ?rst
depth that the spinning tool is forced into the housing 12;.
part being composed of a vmaterial having a strength
and hardness substantially less than the second part, the
After the locators 68 have been formed on the hous
second part bein‘r of substantially rectangular con?gure’
ing E2, the parts are removed from the clamping ?xture.
tion which comprises, clamping the parts in the proper
Since the housing has been matched to a particular frame,
‘the housing and frame must be kept together during all
assembled position, engaging the ?rst part with a ‘rotat
second part, and applying pressure 'to the spinning tool
assembly of the disclosed embodiment, an armature, not
which is only slightly less than the compressive strength
shown, is mounted within the air gap of the frame and an
of the material of the ?rst part to form a locator by
end plate, not shown, is attached to the other end of the
?owing the material of the ?rst part ahead of the tool
frame. A worm gear, not shown, is mounted in the cylin
drical bore 44 of the gear reduction housing 12. When 60 into the corner of the second part due to localized soften
ing of the material of the ?rst part caused by heat gen
all of the subassembly operations are complete, the frame
erated due to frictional engagement between the spinning
and gear reduction housing are reassembled and have a
tool and the ?rst part.
precise ?t by reason of the locators 68 being matched to
the particular frame as shown in FEGURE 5.
From the foregoing it is manifest that the present in
vention teaches a unique method of forming precise lo
cators in a part which must be accurately located with
6. The method of forming locators on a ?rst part
which is to be mated for subsequent assembly with a
second part where the ?rst part is of softer material than
the second part and has a substantially ?at lower surface
engageable with an edge of the second part, including
the steps of clamping the ?rst part over the edge of the
‘a matching part with which it is subsequently assembled.
This is particularly important where size and shape of one 70 second part in proper alignment therewith, and forming
of the mating parts may vary considerably. Moreover,
a plurality of unsymmetrically spaced integral extruded
it is readily apparent that by using parts with extruded
locators depending from the lower ?at surface of the
locators the time required for ?nal assembly of matching
?rst part and engageable with ‘the edge of ‘the second
parts can be substantially reduced.
part to assure proper alignment of the mated parts upon
While the embodiment of the invention as herein dis
subsequent assembly thereof.
‘
3,077,030
6
5
7. The method of forming locators on a ?rst part
which is to be mated for subsequent assembly with a
second part where the ?rst part is of softer material than
the second part and has a substantially ?at lower surface
engageable with an edge of the second part, the edge
surface of the second part having a plurality of corners,
including the steps of clamping the ?rst part over the
edge of the second part in proper alignment therewith,
and forming a plurality of spaced integral extruded loca
tors depending from the hat surface of the ?rst part and
1,812,151
1,842,571
2,198,146
2,273,931
2,306,233
2,375,822
2,496,928
2,565,692
2,572,956
2,795,039
2,870,533
2,885,773
2,902,752
engageable with corners of the edge surface of the sec
0nd part to assure proper alignment of the mated parts
upon subsequent assembly thereof.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,784,256
we“
Stout ________________ __ Dec. 9, 1930
15
Jacocks _____________ __ June
Sebell _______________ __ Jan.
Anderson ____________ __ Apr.
Byrnes ______________ __ Feb.
30,
26,
23,
24,
Smith _______________ __ Dec. 22,
Rose _______________ __ May 15,
Bing _________________ __ Feb. 7,
Koerbacher _________ __ Aug, 28,
1931
1932
1940
1942
194-2
1945
1950
1951
Molinaro ____________ __ May 12,
1951
1957
1959
1959
Keating ______________ __ Sept. 8,
1959
Servis _______________ __ Oct. 30,
Hutchins ____________ __ June 11,
Benham _____________ __ Jan. 27,
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